All, The thread on making shot a few weeks ago was serendipitous. I
really am in need of making my own shot. I’ve experienced some
problems though and was hoping that those of you out there with more
experience could help.
The difficulty is that I seem to get flakes of silver in sizes
ranging from tiny (more like flattened shards of sand) to quite
large and not grain. I bought a 55 gallon container and I drop the
molten silver in the water from a height of almost 6 feet. The
silver I melted in a electomelt at 1850 degrees. I took a ceramic
crucible and drilled seven 2.5 mm holes in it. The crucible was
heated until it glowed red and was white hot at the point the flame
touched it. I know that the melt temperature was on the high end,
but I have to carry the heated crucible about 20 feet outside my
shop and I wanted to make sure that the silver would get through the
crucible; a problem I have experienced before. The silver made it
through pretty well except at the end of the pour it froze.
What say ye? Do I need to use a lower melt temperature? Would
heating the ceramic crucible in the kiln be better than torch
heating? If so, what temperature would be best to hold it at for
how long? Am I better off to use a graphite crucible to pour the
silver through since it holds heat more evenly? Is the problem of
flaking that the metal is hitting the water too hot or is it still
melted and deforming at the bottom of the container?
Normally this is precisely the project I love to experiment on, but
right now I am so busy I need all the help I can get. I’d just
order the shot but I’m looking for certain sizes of shot and if I
order the shot I only get about 10-15 percent usable sizes, so I
have all this extra metal that I really need to recycle.
To get very round shot the old fashioned way was a tall tower to
pour from to allow the shot to solidify before hitting the water
these were on the order of 15-20 feet tall . I think you are just
not getting the time to solidify before the metal hits the water. In
the current shot making I have seen the shotting crucible (with the
holes in it) was held very close to the surface of the water so that
the force of the metal hitting the water would not flatten out the
drops into flakes. The water was being circulated and cooled. The
result is not perfectly round but not so many flakes.
Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160
@James_Binnion
Member of the Better Business Bureau
It seems like you don,t haave the crucible heat constent . Put a
torch flame onto the outside of the crucible and keep it red hot
before you start the pouring process and continue the heating of the
crucible with the ansll holes and This should solve your problem. One
other thing I think your mmetal temp is toohigh . It should have a
mirrow look when it is ready to pour. My metal refiner here in La.
uses this process and his silver shot comes out about bb size He
drilled 6 holes in the botom of the crucible which was about 2’ DIAM
AND 4 TO 6 " DEEP try this and let me know the results.
The shots are not flattened at the bottom of the container, but are
flattened as soon as the melt hits the surface of the cold water.
But firstly there would be a fewdetails required to pin point the
exact cause/s of the hurdle in the project.
Are you trying to make shots with fine silver or sterling silver ?
i-e what is the purity of the metal that you are trying to make the
shots with, and what is thesize of the shotsyou require ?
Secondly, have you made any effort to guess the temperature of the
melt that you are carrying out of your shop? I think the distance to
your shotting unit and the time taken to pour is a big time
consuming factor that will level the high temperature advantage of
your melt. My guess is you are trying to make shots in fine silver
which melts @ 961 Celcius. Normally a 100 degree temperature
difference is sufficient enough temperature buffer to enable you to
pour the melt. I have a few suggestions:
Use a nice flux to cover your melt
Try and reduce the distance between your melting unit and your
shotting unit.
Reduce the perforation size of your crucibles from 2.5mm to maybe
1.5mm. Also counter-sinking the holeson the inside of the crucible
would help.
The water that you are adding the molten metal has to has a swirling
action ( could be clockwise or anti clockwise ) to enable the molten
metal take a spherical shape.
A height of 6 feet is totally un-necessary to do this job. You could
try keeping the perforated crucible at a height of say a few inches
( 6 or 8 ) above the water surface.
You could also try to melt the silver over the shotting unit in the
perforated crucible ( preferably graphite ) so that as soon as the
silver melts it falls into the swirling water below. Of course you
have to be extra cautious and careful to avoid any contact of the
splashing water with the crucible.
Also if you are trying to make shots of fine silver it would yield
more flat shots than a Silver alloy with a lower purity.
I hope this helps. And needless to say you are most welcome to take
suggestions and advise about the safety and other precautions
necessary to carry out the actual process from more learned souls on
Orchid.